WO2019159204A1

WO2019159204A1 - Device for measuring temperature

Info

Publication number: WO2019159204A1
Application number: PCT/IT2018/000022
Authority: WO
Inventors: Rocco TRIVIGNO
Original assignee: M.D. Micro Detectors S.P.A.
Priority date: 2018-02-19
Filing date: 2018-02-19
Publication date: 2019-08-22

Abstract

A device for measuring temperature (1), particularly for industrial applications, comprising a photo-receiver (2) that operates in the infrared spectrum, a signal amplifier, and a processor, such device (1) providing in output an electrical signal corresponding to the thermal image detected with geometric resolution comprised between 320x200 pixels and 2 pixels, each pixel of such image assuming a coloring corresponding to a detected temperature.

Description

DEVICE FOR MEASURING TEMPERATURE

The present invention relates to a device for measuring temperature, particularly for industrial applications.

As devices for measuring temperature, the use is known of thermographic cameras, which use the principle of thermography: a remote sensing technique implemented by way of the acquisition of images in the infrared spectrum.

More precisely, this technique makes it possible to measure the infrared energy emitted by bodies with a temperature different from absolute zero, by way of adapted sensors, and correlate it to the surface temperature of that body.

This procedure concludes with the conversion of the energy emitted to a video signal.

The thermographic camera is therefore an instrument that detects the intensity of the infrared radiation of a body, and not an instrument that sees or detects the temperature.

The limitations on using thermographic cameras are mainly linked to the high cost of the apparatus and the need for a qualified operator, in that the thermographic images provided by thermographic cameras are complex to interpret, in particular for an automatic machine.

Using thermographic cameras therefore implies a considerable investment, to which must be added the costs of training specialist operators.

As devices for measuring temperature, the use is also known of point infrared sensors such as pyrometers and infrared thermocouples.

The main limitation of this type of conventional device is indeed its capacity to detect the temperature only at individual points, and hence the fact that it does not provide an overall picture of the situation.

In fact it is not possible to have any thermal information about the areas adjacent to the single point analyzed by such devices, with the risk that thermal anomalies or hot zones will not be identified during analysis.

The aim of the present invention is to solve the above mentioned drawbacks, by providing a device for measuring temperature, particularly for industrial applications, which can be directly interfaced with devices of the type of automatic machines without the direct intervention of the operator.

Within this aim, an object of the invention is to provide a device for measuring temperature, particularly for industrial applications, of reduced dimensions.

Another object of the invention is to provide a device for measuring temperature, particularly for industrial applications, which makes it possible to have an overall picture of the situation that is being analyzed.

Another object of the present invention is to provide a method and corresponding device for measuring temperature, particularly for industrial applications, which make it possible to recognize the type of material that is being analyzed.

A still further object of the invention is to provide a device for measuring temperature, particularly for industrial applications, which is low cost, easily and practically implemented and safe in use.

This aim and these and other objects which will become better apparent hereinafter are achieved by a device for measuring temperature, particularly for industrial applications, characterized in that it comprises a photo-receiver that operates in the infrared spectrum, a signal amplifier, and a processor, said device providing in output an electrical signal corresponding to the thermal image detected with geometric resolution comprised between 320x200 pixels and 2 pixels, each pixel of said image assuming a coloring corresponding to a detected temperature.

Such aim and such objects are also achieved by a method of identifying the type of materials with a device that comprises a photoreceiver that operates in the infrared spectrum, a signal amplifier, and a processor, said device providing in output an electrical signal corresponding to the thermal image detected with geometric resolution comprised between 320x200 pixels and 2 pixels, which consists of:

a) detecting the infrared radiation emitted by an object, of which the temperature is known, via the photo-receiver.

b) calculating the value of the temperature of the object on the basis of the detection carried out;

c) calculating the emissivity of the object on the basis of the comparison between the calculated temperature and said predefined and known temperature value;

d) determining the type of material of said object on the basis of the comparison between the emissivity value detected and the predefined and known emissivity values of various different types of materials.

Further characteristics and advantages of the invention will become better apparent from the detailed description that follows of a preferred, but not exclusive, embodiment of the device for measuring temperature, particularly for industrial applications, according to the invention, which is illustrated by way of non-limiting example in the accompanying drawings, wherein:

Figure 1 is a perspective view from the front of the device for measuring temperature, particularly for industrial applications, according to the invention;

Figure 2 is a perspective view from behind of the device for measuring temperature, particularly for industrial applications, according to the invention;

Figure 3 is a side view of the device for measuring temperature, particularly for industrial applications, according to the invention;

Figure 4 is a plan view from below of the device for measuring temperature, particularly for industrial applications, according to the invention; Figure 5 is a plan view from above of the device for measuring temperature, particularly for industrial applications, according to the invention.

With reference to the figures, the reference numeral 1 generally designates a device for measuring temperature, particularly for industrial applications.

According to the invention, the device 1 comprises a photo-receiver 2 that operates in the infrared spectrum, a signal amplifier, and a processor.

The device 1 provides in output an electrical signal that corresponds to the thermal image detected with geometric resolution comprised between 320x200 pixels and 2 pixels, each pixel of such image assuming a coloring corresponding to a detected temperature.

Advantageously, such geometric resolution value therefore makes it possible to obtain a thermographic image that can be easily interpreted autonomously by a machine.

In fact, in industrial applications, such as for example, inside an industrial oven for the production of cooked food products, it is not necessary to know with precision the temperature inside the oven but to detect a possible anomalous temperature profile which is in fact an indicator of a potential problem, such as for example a fire.

Detection of this anomalous temperature value can therefore trigger a series of operations which will be executed automatically by the machine, such as for example the immediate interruption of the production process (immediately switching off the oven) and the sending of an alarm signal to the operator attending the machine.

According to a solution of particular utility and practicality, the photo-receiver 2 can be of the type preferably selected from the group comprising the HTPA32x32d sensor made by Heimann, the HTPA80x64d sensor made by Heimann, the AMG8834 sensor made by Panasonic and the like. Furthermore, the device 1 can have a maximum size of 150 cm³.

The device will have dimensions that are compatible with sensor standards and therefore these dimensions will be particularly small with respect to the dimensions of a thermographic camera.

In fact, since it does not need to be used by an operator, it will have no screen, keys or buttons typical of a thermographic camera, elements which make it possible for an operator to easily manage and run it.

The reduced size that distinguishes the device 1 therefore makes it particularly suitable for performing readings and measurements directly on board the machine or on the production line.

According to a preferred solution the device 1 can be cylindrical, of diameter comprised between 10 mm and 20 mm.

According to a preferred solution the photo-receiver 2 can have a geometric resolution comprised between 16x4 pixels and 2 pixels.

It should be noted that the resolution of the photo-receiver 2, according to the invention, is particularly low with respect to that of a thermographic camera, in that the purpose of the device 1 is not to graphically represent the object analyzed in the best way possible (a task for which thermographic cameras for example could be used), but rather to provide a thermographic image that can be interpreted autonomously by an automatic machine.

In industrial applications, in fact, precisely by taking advantage of this peculiarity of the device 1, it will be possible to transfer the electrical signal in output from the device 1 directly to the automatic machine, without requiring the intervention of the operator, with saving of time and cost.

In particular, the photo-receiver 2 can have an operating temperature range, i.e. the thermal scale within which the operator will presumably need to work, comprised between -60°C and 1000°C.

This operating range will also make it possible to use the device 1 for monitoring an object at high temperature. More specifically, the photo-receiver 2 can have a thermal resolution comprised between 0.0001°C and 0.1 °C. Within this range, it should be noted that it has been possible to achieve optimal performance levels using a photo-receiver with a thermal resolution comprised between 0.0001°C and 0.0020°C.

It should be noted that thermal resolution is defined as the maximum difference in terms of degrees that the photo-receiver 2 is capable of resolving on a same image: the greater the thermal resolution is, the greater the accuracy will be of the temperature value that the photo-receiver 2 proper will be able to provide.

The photo-receiver 2 can have a frequency of acquisition that exceeds

2 Hz.

According to a solution of particular effectiveness and efficiency, the device 1 can be associated with a display screen. Such screen will therefore display the thermal image with predefined resolution.

It should be noted that the screen can advantageously indicate the maximum, minimum and average temperature detected.

Furthermore, it will be possible to modify, during observation or at a later time, by way of the software for displaying thermographic images, the temperature field, deciding whether to widen it or narrow it.

This parameter must be adjusted by modifying the range of temperatures of the image displayed.

For example, with a wide range of temperatures it is possible to display a greater number of portions of the object, or objects, at different temperatures: generally, working with a wide range is useful when the investigation is aimed at identifying thermal anomalies or hot points. On the other hand, using a reduced range of temperatures it is possible, once the anomaly or hot point has been identified, to display and highlight only that thermal detail.

The front portion of the device 1 which comprises the photo-receiver 2 can advantageously be removable in order to enable an easy substitution of the photo-receiver 2 proper for different applicative requirements.

In fact, depending on the particular application, it will be possible to use a photo-receiver 2 with different acquisition frequency parameters, thermal resolution, working range, and geometric resolution.

Furthermore, the possibility is not ruled out that the device 1 could comprise at least one connector 3 for connecting the device 1 to an element preferably selected from a group comprising a memory unit, a control and management module, a display screen and the like.

It should be noted that this description also protects the method of identifying the type of material, which is carried out with a device 1 which comprises a photo-receiver 2 that operates in the infrared spectrum, a signal amplifier, and a processor.

Such device 1 provides in output an electrical signal corresponding to the thermal image detected with geometric resolution comprised between 320x200 pixels and 2 pixels.

Such method according to the invention consists of a first step of detecting the infrared radiation emitted by an object, of which the temperature is known, via the photo-receiver 2.

At this point the method proceeds, firstly, with calculating the value of the temperature of the object on the basis of the detection carried out and, subsequently, with calculating the emissivity of the object on the basis of the comparison between the calculated temperature and the known temperature value of the object.

Therefore by knowing the emissivity value detected it will be possible, by way of the comparison with the predefined and known emissivity values of various different types of materials, to determine the type of material of the object that is being analyzed.

It should be noted that emissivity is the measurement of the capacity of a material to emit (emanate) infrared rays. The emissivity therefore varies on the basis of the superficial properties, of the material and, for some materials, also on the basis of the temperature of the object.

It is also true that under determined conditions different materials can have the same emissivity, and consequently using this method it is not possible to identify the type of material absolutely, but it is possible to effectively distinguish, starting from a restricted sample of materials, the type of material that the automatic machine is processing at that exact moment.

Furthermore, if we consider that smooth, brilliant, reflecting and/or glossy surfaces generally have a slightly lower emissivity than opaque, structured, rough, deteriorated and/or scratched surfaces of the same material, then by knowing the emissivity value it is therefore possible to effectively distinguish whether or not the material being worked on has a given surface finish, or to detect a discrepancy in the finish of the object.

Advantageously, the device 1 for measuring temperature, particularly for industrial applications, can be directly interfaced with devices of the type of automatic machines without the direct intervention of the operator.

Conveniently, the device 1, according to the invention, is reduced in size.

Conveniently, the device 1 for measuring temperature, particularly for industrial applications, makes it possible to have an overall picture of the situation that is being analyzed.

Effectively, the method and corresponding device 1 for measuring temperature, particularly for industrial applications, make it possible to recognize the type of material that is being analyzed.

Conveniently, the device for measuring temperature 1 is low cost, easily and practically implemented and safe in use.

The invention, thus conceived, is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims. Moreover, all the details may be substituted by other, technically equivalent elements.

In the embodiments illustrated, individual characteristics shown in relation to specific examples may in reality be interchanged with other, different characteristics, existing in other embodiments.

In practice, the materials employed, as well as the dimensions, may be any according to requirements and to the state of the art.

Where the technical features mentioned in any claim are followed by reference numerals and/or signs, those reference numerals and/or signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly, such reference numerals and/or signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference numerals and/or signs.

Claims

1. A device for measuring temperature, particularly for industrial applications, characterized in that it comprises a photo-receiver (2) that operates in the infrared spectrum, a signal amplifier, and a processor, said device (1) providing in output an electrical signal corresponding to the thermal image detected with geometric resolution comprised between 320x200 pixels and 2 pixels, each pixel of said image assuming a coloring corresponding to a detected temperature.

2. The device according to claim 1, characterized in that said photoreceiver (2) is of the type preferably selected from the group comprising the HTPA32x32d sensor made by Heimann, the HTPA80x64d sensor made by Heimann, the AMG8834 sensor made by Panasonic and the like.

3. The device according to claim 1, characterized in that it has a maximum size of 150 cm³.

4. The device according to one or more of the preceding claims, characterized in that said photo-receiver (2) has a geometric resolution comprised between 16x4 pixels and 2 pixels.

5. The device according to one or more of the preceding claims, characterized in that said photo-receiver (2) has an operating temperature range comprised between -60°C and 1000°C.

6. The device according to one or more of the preceding claims, characterized in that said photo-receiver (2) has a thermal resolution comprised between 0.0001°C and 1° C.

7. The device according to the preceding claim, characterized in that said photo-receiver (2) has a thermal resolution comprised between 0.0001°C and 0.0020°C.

8. The device according to one or more of the preceding claims, characterized in that said photo-receiver (2) has a frequency of acquisition that exceeds 2 Hz.

9. The device according to one or more of the preceding claims, characterized in that it is associated with a display screen, said screen displaying said thermal image with predefined resolution.

10. The device according to claim 1, characterized in that a front portion of said device (1), which comprises said photo-receiver (2), is removable in order to enable an easy substitution of said photo-receiver (2) for different applicative requirements.

11. A method of identifying the type of materials with a device (1) that comprises a photo-receiver (2) that operates in the infrared spectrum, a signal amplifier, and a processor, said device (1) providing in output an electrical signal corresponding to the thermal image detected with geometric resolution comprised between 320x200 pixels and 2 pixels, which consists of:

a) detecting the infrared radiation emitted by an object, of which the temperature is known, via the photo-receiver (2);